Yeah I was gonna mention getting the sample from the filter as well… we had to do that too… sometimes they would just ask us for the entire filter, others pour the oil out from the filter…
JP From: Della Barba, Joe via CnC-List <[email protected]> Sent: Friday, October 16, 2020 5:40 AM To: Stus-List <[email protected]> Cc: Della Barba, Joe <[email protected]> Subject: Stus-List Re: Engine Hours Some airplanes have a magnetic oil drain plug with two electrical probes connected to a light. When the light goes on that means enough metal got stuck on there to complete the circuit and then you get to stare at the light until you land :( Another thing we did with airplanes is cut the filters open when changing the oil to see what was caught in there. Speaking of oil analysis, we always thought you needed several - it was the trend you were looking for unless a number was really high. Another oil related issue – an oil temperature gauge is a nice thing. Too hot is bad, but too cold is bad as well. You want to get the oil up to about 180 degrees or it builds up water and contaminants. Joe Della Barba Coquina C&C 35 MK I www.dellabarba.com <http://www.dellabarba.com> From: [email protected] <mailto:[email protected]> [mailto:[email protected]] Sent: Friday, October 16, 2020 7:55 AM To: 'Stus-List' <[email protected] <mailto:[email protected]> > Subject: [EXTERNAL] Stus-List Re: Engine Hours Hi All, In a previous life I had to do oil samples on heavy equipment and aircraft engines (both piston and turbine). Some of these pieces of equipment or aircraft would run 24/7 so oil samples were taken weekly…(every 100 hours is a common number for production equipment to be sampled) The oil analysis would come back from the lab and it would contain information on a variety of things… the most important thing to the owners and operators of the equipment was the metal content in the oil. As engines are used (and thus tend to wea) parts of the engine are “ground off” and wind up in the oil. By analyzing the metallic content really good analysts could determine exactly what part inside the engine was breaking down… but usually they were just looking for the aggregate amount of metal shavings/dust/chips etc. There is usually some tiny teeny-weeny little bit of metal in the oil (especially on high-hour engines), but over a certain level or amount of metal , the managers of the equipment would be concerned and sometimes even take a piece of equipment out of service and tear the engine down and rebuild it or replace it. Another thing they did was determine if there was soot or carbon from the combustion process, water in the oil, fuel, coolant, dust, dirt, or silica. All of these were indicative of different problems in the engine. Again, most tests will come back with some small amount of each depending on how infinite or precise the sample testing is. As an example if there was “dirt” or grit, sand, silica etc in the oil, this may indicate bad fuel, bad fuel filler spout, bad fuel cap, air filter(s), or air filter housing or hosing. If the sample had coolant in it, then they might look at the cylinder heads, or if there was soot, valves or rings may be the problem… all kinds of things can be divined from the oil sample if read by a knowledgeable person. Me- I just took the samples, logged the results, and ate lunch 😊 JP
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